Train is a vehicle which is more efficient compared with other type of vehicles. Advance technology application is needed in order to increase this efficiency. PT INKA have tried to do this by designing trains which have body

made of composite material in sandwich panel type. The application of this technology requires research and testing to be done first to check the strength and stiffness of the new train. The checking of the strength and stiffness is done by several methods, which are the train testing method based on JIS E7105 standard, and strength analysis of the sandwich panel. Based on JIS E7105, the strength and stiffness testing is done

by two methods: measuring natural frequency, and observing the stress and deflection by giving four types of loading. These four types of loading are differed based on the type of load and support given, such as vertical load, compression load, torsion load, an three points support load. In the other hand, the strength analysis of the sandwich panel is checking done by sandwich panel failure criteria such as face yielding, face wrinkling and core failure because of shear stress. In this step, the method used to define stress, deflection and stress needed in those methods is done by applying finite element analysis using Pro Engineer Wildfire 3.0 program.

This checking provides information that rail bus experienced failure at compression and torsion loading. Therefore, under-frame geometric modification is needed to be done, especially on the under-frame connector part to the other couch. In the other hand, natural frequency checking of rail bus and strength of the sandwich panel shows that the rail bus condition meets the standard.

Modification suggestion given is to add fillet and web on the under-frame connector part.